But if it takes off, Google could eventually use +1 as a sort of social graph overlaying over the Web -- much like Facebook has done by letting sites put those "Like" buttons everywhere.

It could also use +1 to bring content from Google News and other sources into a real-time personalized news feed, like the Facebook home page or Twitter feed.

But this isn't Google's first crack at becoming more social. The company has been trying to get into the social space ever since Friendster launched in 2002 -- Google tried to buy it but was shot down.

Some of these products have done OK. Others have failed so utterly, you've probably forgotten their names -- if you ever knew them to begin with.

1/

Orkut: big in Brazil

After Friendster said "no thanks" to Google's takeover bid -- one of the greatest mistakes in corporate history -- Google got employee Orkut Buyukkokten to build a competing social network. It launched in 2004 and for some reason got huge in Brazil. It's still big there today -- and has very little traction in the rest of the world.

2/

Dodgeball: killed after 4 years.

Google bought this social-mobile-local company in 2005, before those three buzzwords appeared in every startup pitch.

But the product withered inside Google, and the company killed it in 2009 to make way for Google Latitude. Meanwhile, cofounder Dennis Crowley went on to create the popular -- and competing -- social mobile service Foursquare.

3/

Picasa Web: surpassed by Facebook Photos.

But users saw little reason to go to a separate photo-sharing site when they could simply upload photos to Facebook and immediately share them with friends and family on the service -- without sending them to a separate URL.

4/

OpenSocial: ignored by Facebook...and irrelevant to most users.

Google

Google unveiled this open API platform, built in conjunction with MySpace and other social networks, in 2007. The idea was to provide a way for sites to access data stored in all social networks.

There was only one problem: Facebook was busy building its own competing platform. Without the support of the largest social network, the coalition started to falter a few months later, and today few developers consider it a serious competitor to the Facebook Platform.

5/

Jaiku: cut loose after 2 years.

In 2007, Google bought this company, which is like Twitter with a few twists -- like the ability to put icons into messages. Twitter quickly surpassed it, and n 2009, Google stopped developing the product and released its code into the open-source wilderness.

6/

Wave: users didn't understand it.

This service offered real-time collaboration -- sort of like instant messaging meets an old-school bulletin board, wrapped up in Gmail. It could have made an interesting enterprise tool, but Google pitched it at consumers, who didn't understand what it was for. Google discontinued development in summer 2010.

7/

Buzz: misfired on privacy.

Buzz is a Facebook-like news feed that launched in Gmail last February. The idea might have gotten some traction, but Google messed up on the privacy settings -- it basically shared information about your Gmail habits with other Buzz users, and wasn't always clear about who was able to see what. The end result: the FTC investigated, and now will be watching Google's privacy practices with a microscopic eye for the next 20 years.

8/

Aardvark: outbuzzed by Quora.

In February 2010, Google paid $50 million to buy this "social Q&A" company, which lets you post questions to be answered by experts in your area. But Google hasn't done much with the service since -- it's not integrated into Google's core search results -- and Q&A service Quora has gone on to become the darling of the tech set in Silicon Valley.

9/

Slide: too early to call.

Google bought social-app company Slide last summer for around $200 million, and continues to operate it as a pseudo-independent company within Google. Slide recently released a group messaging app called Disco, but that's about it.

10/

So will +1 do any better?

Google's +1 social search service has a couple of legs up on these other social initiatives. First, it's refreshingly simple -- unlike Wave, for example. Second, it's an add-on to Google's core business of search, so it probably won't be allowed to wither and die quietly.

But it probably won't be enough to stop Facebook and other social services like Twitter from grabbing an increasing share of attention and time from users. And where the users go, eventually the ad dollars follow.

Google is still a great place to find general information, and adding a social element will make that information better. But it won't replace the interactions between friends, colleagues, and respected strangers that take place every day on Facebook, Twitter, and other rising social sites like LinkedIn.

11/

Google may be a stiff in social, but there's one area where it's done great.